These results represent the first identification of AX-mediated haptenation of intracellular proteins. Moreover, they show that exosomes can constitute a novel vehicle for haptenated proteins, and raise the hypothesis that they could provide antigens for activation of the immune system during the allergic response.

Drug hypersensitivity reactions result from the activation of the immune system by drugs or their metabolites. The clinical presentations of drug hypersensitivity can range from relatively mild local manifestations to severe systemic syndromes that can be life-threatening. As in other allergic reactions, the causes are multifactorial as genetic, metabolic and concomitant factors may influence the occurrence of drug hypersensitivity. Formation of drug protein adducts is considered a key step in drug adverse reactions, and in particular in the immunological recognition in drug hypersensitivity reactions. Nevertheless, non-covalent interactions of drugs with receptors in immune cells or with MHC clefts and/or exposed peptides can also play an important role. In recent years, development of proteomic approaches has allowed the identification and characterization of the protein targets for modification by drugs in vivo and in vitro, the nature of peptides exposed on MHC molecules, the changes in protein levels induced by drug treatment, and the concomitant modifications induced by danger signals, thus providing insight into context factors. Nevertheless, given the complexity and multifactorial nature of drug hypersensitivity reactions, understanding the underlying mechanisms also requires the integration of knowledge from genomic, metabolomic and clinical studies.

Clavulanic acid (CLV) and amoxicillin, frequently administered in combination, can be independently involved in allergic reactions. Protein haptenation with β-lactams is considered necessary to activate the immune system. The aim of this study was to assess the suitability of biotinylated analogues of CLV as probes to study protein haptenation by this β-lactam. Two synthetic approaches afforded the labeling of CLV through esterification of its carboxylic group with a biotin moiety, via either direct binding (CLV-B) or tetraethylenglycol linker (CLV-TEG-B). The second analogue offered advantages as solubility in aqueous solution and potential lower steric hindrance for both intended interactions, with the protein and with avidin. NMR reactivity studies showed that both CLV and CLV-TEG-B reacts through β-lactam ring opening by aliphatic amino nitrogen, however with different stability of resulting conjugates. Unlike CLV conjugates, that promoted the decomposition of clavulanate fragment, the conjugates obtained with the CLV-TEG-B remained linked, as a whole structure including biotin, to nucleophile and showed a better stability. This was a desired key feature to allow CLV-TEG-B conjugated protein detection at great sensitivity. We have used biotin detection and mass spectrometry (MS) to detect the haptenation of human serum albumin (HSA) and human serum proteins. MS of conjugates showed that HSA could be modified by CLV-TEG-B. Remarkably, HSA preincubation with CLV excess only reduced moderately the incorporation of CLV-TEG-B, which could be attributed to different protein interferences. The CLV-TEG-B fragment with opened β-lactam was detected bound to the 404–430HSA peptide of the treated protein. Incubation of human serum with CLV-TEG-B resulted in the haptenation of several proteins that were identified by 2D-electrophoresis and peptide mass fingerprinting as HSA, haptoglobin, and heavy and light chains of immunoglobulins. Taken together, our results show that tagged-CLV keeps some of the CLV features. Moreover, although we observe a different behavior in the conjugate stability and in the site of protein modification, the similar reactivity indicates that it could constitute a valuable tool to identify protein targets for haptenation by CLV with high sensitivity to get insights into the activation of the immune system by CLV and mechanisms involved in β-lactams allergy.

Tumor suppressors represent a critical line of defense against tumorigenesis. Their mechanisms of action and the pathways they are involved in provide important insights into cancer progression, vulnerabilities, and treatment options. While nuclear and cytosolic tumor suppressors have been extensively investigated, relatively little is known about tumor suppressors localized within the mitochondria. However, recent research has begun to uncover the roles of these important proteins in suppressing tumorigenesis. Here we review this newly developing field and summarize available information on mitochondrial tumor suppressors.

Table of contentsOral AbstractsO1 Functionally distinct HMGB1 isoforms correlate with physiological processes in drug-induced SJS/TENDaniel F. Carr, Wen-Hung Chung, Rosalind E. Jenkiins, Mas Chaponda, Gospel Nwikue, Elena M. Cornejo Castro, Daniel J. Antoine, Munir PirmohamedO2 Hypersensitivity reactions to beta-lactams, does the t cell recognition pattern influence the clinical picture?Natascha Wuillemin, Dolores Dina, Klara K. Eriksson, Daniel YerlyO3 Specific binding characteristics of HLA alleles associated with nevirapine hypersensitivityRebecca Pavlos, Elizabeth Mckinnin, David Ostrov, Bjoern Peters, Soren Buus, David Koelle, Abha Chopra, Craig Rive, Alec Redwood, Susana Restrepo, Austin Bracey, Jing Yuan, Silvana Gaudieri, Mary Carrington, David Haas, Simon Mallal, Elizabeth PhillipsO4 Do we need to measure total ige for the interpretation of analytical results of ImmunoCAP dnd 3gAllergy specific IgE?Douwe De Boer, Paul Menheere, Chris Nieuwhof, Judith BonsO5 Neutrophil activation in systemic anaphylaxis: results from the multicentric NASA studyFriederike Jonsson, Luc De Chaisemartin, Vanessa Granger, Caitlin Gillis, Aurelie Gouel, Catherine Neukirch, Fadia Dib, Pascale Roland Nicaise, Dan Longrois, Florence Tubach, Sylvie Martin, Pierre Bruhns, NASA Study GroupO6 Purpuric drug eruptions due to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) for non-small-cell lung cancer (NSCLC): a clinic-pathological study of 32 casesKai-Lung Chen, Shu-Ling Liao, Yi-Shuan Sheen, Yung-Tsu Cho, Che-Wen Yang, Jau-Yu Liau, Chia-Yu ChuPoster presentations: Poster Walk 1—Anaphylaxis (P01–P09)P1 Anaphylactic reactions during anaesthesia and the perioperative periodRita Aguiar, Anabela Lopes, Natália Fernandes, Leonor Viegas, M. A. Pereira-BarbosaP2 Anaphylaxis to chlorhexidine: is there a cross-reactivity to alexidine?Antonia Bünter, Nisha Gupta, Tatjana Pecaric Petkovic, Nicole Wirth, Werner J. Pichler, Oliver HausmannP3 Cefotaxime-induced severe anaphylaxis in a neonateMehtap Yazicioglu, Pinar G. Ozdemir, Gokce Ciplak, Ozkan KayaP4 Clinical features and diagnosis of anaphylaxis resulting from exposure to chlorhexidinePeter John CookeP5 Drug-induced anaphylaxis: five-year single-center surveyInês Mota, Ângela Gaspar, Filipe Benito-Garcia, Marta Chambel, Mário Morais-AlmeidaP6 Intraoperative severe anaphylactic reaction due to patent blue v dyeLuis Marques, Eva Alcoceba, Silvia LaraP7 Kounis syndrome in the setting of anaphylaxis to diclofenacLeonor Carneiro-Leão, Carmen Botelho, Eunice Dias-Castro, Josefina CernadasP8 Perioperative anaphylaxis audit: Royal Melbourne HospitalKatherine Nicholls, William Lay, Olivia Smith, Christine Collins, Gary Unglik, Kymble Spriggs, Priscilla Auyeung, Jeremy McComish, Jo A. DouglassP9 Recurrent peri-operative anaphylaxis: a perfect stormJonny G. Peter, Paul PotterPoster Walk 2: DH regions and patient groups (P10–P19)P10 A rare presentation of amoxicillin allergy in a young childFabrícia Carolino, Eunice Dias De Castro, Josefina R. CernadasP11 Adverse drug reactions in ...